Opaque Adhesives in Wet Condition for Label Application

ABSTRACT

Various opacifying adhesive compositions are described. The adhesives exhibit relatively high levels of opacity in wet conditions while maintaining acceptable adhesive properties. Also described are label assemblies and labeled containers using such adhesives. Related methods of use and preparation are also described.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application claims the benefit of Indian ProvisionalApplication No. 1726/MUM/2015 filed on Apr. 30, 2015, which isincorporated herein by reference in its entirety.

FIELD

The present subject matter relates to adhesive compositions that remainopaque in wet condition and may be used for pressure sensitiveapplications including but not limited to label constructions, andgraphic and reflective constructions. The present subject matter alsorelates to methods of preparation of the adhesives and construction ofthe labels. The present subject matter additionally relates to labeledarticles using the adhesives. The labels are particularly useful forapplication in wine and beverages wherein the label does not lose itsopacity when the label along with its accompanying container issubjected to moisture, water or humidity for cooling.

BACKGROUND

A label is often the primary resource for evaluating wine or beveragesbefore making a purchase. Moreover, wineries place great importance onlabel design as appearance of label is known to influence wine buyingchoices. A majority of wine and beverage bottles use paper as labelfacestock because of its perceived superior aesthetic appearance andshelf appeal. Paper facestocks are however, susceptible to losingopacity when exposed to moisture, humidity and water during cooling orstoring. During the period of cooling, liquid infuses into suchfacestocks and causes the appearance of the paper to changeunacceptably. Additionally, the facestock might pucker, further reducingappearance.

It is also observed in certain cases that irrespective of the nature ofthe facestock being used in the label, moisture and related componentscan adversely affect the adhesive holding the label to the bottle andthe label may become detached which causes identification even moredifficult.

Attempts have been made or solutions have been proposed in the past toprovide or improve general opacity of labels. These attempts, howevereither failed to recognize the opacity problem of labels in wetconditions, and were ineffective or expensive or both.

In addition to the past attempts to devise a solution to improve opacityin labels, the conventional art provides general solutions to dryopacity. The solutions include addition of pigments, such as titaniumdioxide, calcium carbonate, aluminium silicate, calcined clay, kaolinclay, and zinc oxide. The pigments can be added to the paper facestocklayer during the paper making process. The pigments can also be added asa coating layer such as an undercoat or topcoat on the paper facestockand the coat can be placed between the facestock and a pressuresensitive adhesive layer.

A significant limitation with those pigments is that many of thosepigments such as calcium carbonate, aluminium silicate, calcined clay,kaolin clay, and zinc oxide show good dry opacity but exhibit poor wetopacity. Titanium dioxide even though showing better wet opacity, cannotbe used in the suggested way because titanium dioxide is significantlyexpensive. Also manufacturers of labels do not have control on papermanufacturing so as to be able to incorporate desired levels of pigmentinto the paper. Moreover, use of pigments in coating layers involvesmultiple steps that are often complex requiring special processingrequirement and thus adding further to cost of manufacturing. Thusutilization of the pigments, while attractive, has not been general.

Accordingly, a need exists for a new strategy for labelling articles sothat the labels maintain a relatively high level of opacity when in awet condition, while also maintaining adhesive properties.

SUMMARY

The difficulties and drawbacks associated with previous approaches areaddressed in the present subject matter as follows.

In view of the foregoing, a pressure sensitive construction adapted toremain opaque in wet conditions is provided. The pressure sensitiveconstruction includes an outer layer of facestock for receiving printedindicia, at least one opacifying adhesive layer underlying thefacestock, and a liner underlying the opacifying adhesive layer. Theopacifying adhesive layer includes an adhesive component and a pigmentcomponent in proportion sufficient to maintain opacity when exposed toan aqueous environment for at least 1 hour while maintaining peeladhesion and loop tack of the opacifying adhesive layer when applied toa substrate.

The label laminate may further include an adhesive layer underlying theopacifying adhesive layer. The adhesive layer may be selected from thegroup including emulsion adhesives, hot-melt adhesives, solventadhesives and/or a combination thereof.

In another aspect of the subject matter, a label or laminate adapted toremain opaque in wet condition for pressure sensitive application isprovided. The laminate may include an outer layer of facestock forreceiving printed indicia, a first opacifying adhesive layer and asecond opacifying adhesive layer. The first opacifying adhesive layerunderlies the facestock. The second opacifying adhesive layer mayunderlie the first opacifying adhesive layer. The first opacifyingadhesive layer may include a first adhesive component and a firstpigment component in a proportion sufficient to maintain opacity whenexposed to an aqueous environment for at least 1 hour with sufficientpeel adhesion and loop tack of the first opacifying adhesive layer inthe pressure sensitive application. The second opacifying adhesive layermay include a second adhesive component and a second pigment componentin a proportion sufficient to maintain opacity when exposed to anaqueous environment for at least 1 hour with sufficient peel adhesion orloop tack of the second opacifying adhesive layer in the pressuresensitive application. The laminate may additionally include a linerunderlying the second opacifying adhesive layer.

In yet another aspect of the subject matter, an opacifying adhesivecomposition adapted to remain opaque in wet condition for pressuresensitive label application is provided. The opacifying adhesive mayinclude a proportionate amount of adhesive component and a pigmentcomponent sufficient to maintain opacity when exposed to an aqueousenvironment for at least 1 hour with sufficient peel adhesion and looptack in the pressure sensitive application.

In a further aspect of the subject matter, a method of preparation of anopacifying adhesive composition which is adapted to remain opaque in wetcondition for pressure sensitive label application is provided. Themethod may include the steps of mixing a proportionate amount of anadhesive component and a pigment component with constant agitation, andcontinuing the mixing for a desired time period such as for exampleabout 20 minutes. The opacifying adhesive does not cause anyunacceptable loss of peel adhesion or tack of the adhesive component inpressure sensitive application.

In still another aspect of the present subject matter, a labeled articleis provided in which the label maintains a relatively high degree ofopacity in a wet condition while also exhibiting sufficient peeladhesion and loop tack. The label is adhered to the article by a layerof an opacifying adhesive that includes a proportionate amount ofadhesive component and a pigment component.

As will be realized, the subject matter described herein is capable ofother and different embodiments and its several details are capable ofmodifications in various respects, all without departing from theclaimed subject matter. Accordingly, the drawings and description are tobe regarded as illustrative and not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustrative embodiment of a cross-sectional view of alabel having an opacifying adhesive layer in accordance with the presentsubject matter.

FIG. 2 is an illustrative embodiment of a cross-sectional view of alabel having an opacifying adhesive layer and an adhesive layer inaccordance with the present subject matter.

FIG. 3 is an illustrative embodiment of a cross-sectional view of alabel having a first opacifying layer and second opacifying layer inaccordance with the present subject matter.

FIG. 4 is an illustrative embodiment of a cross-sectional view of alabel having a filmic and/or metal layer in accordance with the presentsubject matter.

FIG. 5 is an illustrative embodiment of a cross-sectional view of alabel having a clear or transparent film layer in accordance with thepresent subject matter.

FIG. 6 is a schematic illustration of a labeled article such as a bottlein accordance with an embodiment of the present subject matter.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present subject matter is not limited to the particular embodimentsdescribed herein, and may vary. It is also to be understood that theterminology used herein is for the purpose of describing particularembodiments only, and is not intended to be limiting. Where a range ofvalues is provided, it is understood that each intervening value, to thetenth of the unit of the lower limit unless the context clearly dictatesotherwise, between the upper and lower limit of that range and any otherstated or intervening value in that stated range is encompassed withinthe subject matter. The upper and lower limits of these smaller rangesmay independently be included in the smaller ranges is also encompassedwithin the subject matter, subject to any specifically excluded limit inthe stated range. Where the stated range includes one or both of thelimits, ranges excluding either or both of those included limits arealso included in the subject matter.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this subject matter belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the present subject matter, a limitednumber of the exemplary methods and materials are described herein.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include plural referents unless thecontext clearly dictates otherwise.

The embodiments of the present subject matter will be better understoodin terms of their components, structure and effectiveness from thefollowing detailed description with reference to the figures and datadepicting various results. Various objects, features, aspects, andadvantages of the present subject matter will become more apparent fromthe following detailed description of various embodiments of the subjectmatter along with accompanying drawings.

The embodiments of this subject matter result from the unexpecteddiscovery that when a particular adhesive is proportionally mixed withone or more suitable opacifying components such as pigments, anopacifying adhesive results which can be used in a pressure sensitiveadhesive application that maintains opacity in wet condition withoutcompromising required adhesive properties.

It is typically understood by those having ordinary skill in the artthat mixing pigments with adhesive is undesirable as addition of pigmentis known to reduce adhesive strength and tack of adhesive. Specifically,it is reported that an addition of 20% TiO₂ in pressure sensitiveadhesive (PSA) reduces tack by more than 50% and peel by 50%. SeeDonatas Satas, Handbook of Pressure Sensitive Adhesive Technology, ThirdEdition, Warwick, Satas & Associates, 1999, Chapter-19, Table 19-5, TheEffect of Various Fillers.

Pressure sensitive adhesives (PSA's) are typically characterized by theability of the adhesive to withstand creep or shear deformation, whileexhibiting adequate tack and peel adhesion properties. This balance ofproperties is derived from the structure of the main polymer bulk whichmakes up the PSA. It is characterized by a high molecular weight, whichprovides the necessary cohesive strength and resistance to sheardeformation, and by a low modulus of the polymer backbone, which allowsthe polymer to conform to a substrate surface upon contact. It is alsoimportant that PSA's should perform in wide range of substrates to whichthe adhesive may be attached and such substrates include glass, plasticssuch as high density polyethylene (HDPE), wood, metal and the like.Accordingly, any adverse effect on adhesive property such as peeladhesion and tack typically results from mixing of additive into theadhesive, and significantly limits applicability of the adhesive inpressure sensitive constructions, particularly for label applicationswhich are intended to withstand wet environments.

An embodiment of a pressure sensitive construction of a label laminateis shown in FIG. 1. The label of laminate 100 is adapted to remainopaque in wet condition/environment. The laminate 100 includes an outerlayer of facestock 102, an opacifying adhesive layer 104 and a liner106. The face stock 102 has a first surface 108 and a second surface112. The first surface 108 of the face stock is meant to receive indiciasuch as printed indicia or other text or symbols. The opacifyingadhesive layer 104 underlies the second surface 112 of the face stock102. The liner 106 underlies the opacifying adhesive layer 104.

The opacifying adhesive layer includes an adhesive component and apigment component in a proportion sufficient to cause/maintain opacitywhen wet, while maintaining peel adhesion and loop tack of the adhesivecomponent in pressure sensitive applications. That is, there is nounacceptable loss in peel adhesion and/or loop tack. The opacity of thelabel in wet condition may be in range of from about 70% to about 100%in many embodiments, from about 75% to about 95% in certain embodimentsand from about 80% to about 90% in particular embodiments. All opacityvalues noted herein are overall opacity values taken across a thicknessof a label assembly as described herein, unless noted otherwise. Opacityis measured as described herein in the description of various examplesof the present subject matter.

The expression “while maintaining peel adhesion and tack of the adhesivecomponent” as used herein refers to a comparison of such properties ofan adhesive without any pigment (fillers) and an adhesive with pigments.

The term “no unacceptable loss of peel adhesion” refers to a loss inpeel adhesion of less than 90%, in many embodiments less than 80%, lessthan 70%, less than 60%, less than 50%, less than 40%, less than 30%,less than 20%, less than 10%, and in certain embodiments less than 5%when the pigment is added compared to the nonpigmented adhesive underdry conditions.

The term “no unacceptable loss of loop tack” refers to a loss in looptack of less than 90%, in many embodiments less than 80%, less than 70%,less than 60%, less than 50%, less than 40%, less than 30%, less than20%, less than 10%, and in certain embodiments less than 5% when thepigment is added compared to the nonpigmented adhesive under dryconditions.

The adhesive component may be a pressure sensitive adhesive and thepressure sensitive adhesive component may be selected from the groupconsisting of emulsion adhesives, hot-melt adhesives, solvent adhesives,and/or combinations thereof.

Various commercially available adhesive formulations can be used as theadhesive component of the opacifying adhesives of the present subjectmatter. Nonlimiting examples of such adhesive formulations include butare not limited to S2000N, S692N, AT20N all available from AveryDennison; H9232 available from BASF; and XPE1045 available from AveryDennison. It will be appreciated that the present subject matter is notlimited to any particular adhesive component, and includes a wide arrayof such components.

The pigment component in the opacifying adhesive layer can be selectedsuch that the pigment exhibits acceptable wet opacity when present alongwith the noted adhesive component. The pigment component may be presentin a weight range of about 10% to about 50% of the adhesive component inmany embodiments, in a range of about 15% to about 45% in certainembodiments, and from about 20% to about 40% in particular embodiments.In many embodiments the pigment may include titanium dioxide TiO₂.Various commercially available TiO₂ formulations and materials can beused as the pigment component in the opacifying adhesives of the presentsubject matter. The pigment may utilize other pigments instead of, or inaddition to, titanium dioxide such as structured calcium carbonates(PCCs), barium sulphate, calcined clay, and aluminium silicates.

In certain embodiments, the opacifying adhesives of the present subjectmatter utilize coated or surface treated TiO₂ in the pigment component.In particular applications, the surface coated TiO₂ maintains arelatively high dispersal level within the opacifying adhesive inaddition to exhibiting other benefits and/or advantages.

The pressure sensitive construction may further comprise an adhesivelayer underlying the opacifying adhesive layer which is detailedhereinafter in reference to FIG. 2.

The pressure sensitive application may be performed on nearly anysubstrate that may include but not limited to glass, plastic, metalsubstrate, high density polyethylene (HDPE), wood, metal, plastic or anyother substrate related to bottling and packaging commonly known in theart and useful as containers.

The facestock may comprise paper facestock, plastic facestock, amultilayer laminated facestock including both paper and plastic layers,or any other materials that are commonly used in the industry.

The pressure sensitive construction of labels may have loop tack whichis greater than about 8, greater than about 12, greater than about 16,and more particularly greater than about 20 newtons per inch (N/inch)when the facestock being used is paper, and when the pressure sensitiveapplication being is performed on a glass substrate. The label may haveloop tack which is greater than about 4, greater than about 8, and moreparticularly greater than 12 newtons per inch (N/inch) when thefacestock is paper, and when the pressure sensitive application isperformed on a high density polyethylene (HDPE) substrate. Generally,for many combinations of substrates and facestocks, the labels of thepresent subject matter exhibit loop tack values greater than about 2 andtypically at least about 3 N/inch. However, it will be appreciated thatthe present subject matter is not limited to any of these particularloop tack ranges or values, and instead includes other loop tack values.Loop tack values as described herein are measured using Finat testmethod FTM-9 using a pull rate of 300 mm/min at room temperature.

The pressure sensitive construction of labels may exhibit a peeladhesion of at least 1 and in certain embodiments at least 2 N/inchafter 24 hours bond time. In certain embodiments the labels exhibit apeel adhesion of at least 4, at least 6, at least 8, and in certainversions at least 10 N/inch. However, it will be understood that thepresent subject matter includes labels exhibiting a wide range of peeladhesion values and is not limited to these representative values. Peeladhesion 90° values are measured using Finat test method FTM-2 using apull rate of 300 mm/min at room temperature.

In many embodiments, the coat weight of the opacifying adhesive is fromabout 5 to about 30 grams per square meter (gsm). According to certainembodiments herein, the opacifying adhesive layer can have a coat weightof from about 16 to about 40 grams per square meter (gsm). Theopacifying adhesive layer may have a coat weight, more particularly fromabout 22 to about 30 grams per square meter (gsm).

Another embodiment of pressure sensitive construction of a labellaminate which is adapted to remain opaque in wet environment is shownin FIG. 2. The label laminate 200 includes an outer layer of facestock202, an opacifying adhesive layer 204, an adhesive layer 206, and aliner 208. The face stock 202 has a first surface 210 and a secondsurface 212. The first surface 210 of the face stock is meant to receiveindicia such as printed or others text or symbols. The opacifyingadhesive layer 204 underlies the second surface 212 of the face stock202. The adhesive layer 206 underlies the opacifying layer 204. Theliner 208 underlies the adhesive layer 206.

The opacity of the label laminate 200 may be similar to the laminate 100and the composition/content of the opacifying adhesive layer 204 may besimilar to opacifying adhesive layer 104 according to an embodimentherein. In certain embodiments, the pigment component of the opacifyingadhesive layer 204 can be more than 80% or more than 90% of the adhesivecomponent.

The adhesive layer 206 may be selected from the group consisting ofemulsion adhesives, hot-melt adhesives, solvent adhesives, and/orcombinations thereof.

In a particular embodiment, the adhesive component may include acrylicadhesive.

The adhesive layer 206 may have a coat weight of about 8 to 20 gsmaccording to an embodiment herein.

In certain embodiments, the label 200 has loop tack which is greaterthan 8 newtons per inch (N/inch) when the facestock being used is paper,and when the pressure sensitive application is performed on a glasssubstrate. The label 200 may have loop tack which is greater than 4newtons per inch (N/inch) when the facestock being used is paper, andwhen the pressure sensitive application is performed on a high densitypolyethylene (HDPE) substrate.

Another embodiment of a pressure sensitive construction of a labellaminate which is adapted to remain opaque in wet condition is shown inFIG. 3. The label laminate 300 includes an outer layer of facestock 302,a first opacifying adhesive layer 304, a second opacifying adhesivelayer 306, and a liner 308. The first opacifying adhesive layer 304underlies the facestock 302. The facestock 302 defines oppositelydirected faces 310 and 312 as previously described. The liner 308underlies the second opacifying adhesive layer 306. The first opacifyingadhesive layer 304 includes a first adhesive component and a firstpigment component in a proportion sufficient to maintain opacity whenwet with no unacceptable loss of peel adhesion or loop tack of the firstopacifying adhesive layer 304 in the pressure sensitive application. Thesecond opacifying adhesive layer 306 includes a second adhesivecomponent and a second pigment component in a proportion sufficient tomaintain opacity when wet with no unacceptable loss of peel adhesion orloop tack of the second opacifying adhesive layer 306 in the pressuresensitive application.

The first adhesive component and the second adhesive component may beselected from the group consisting of emulsion adhesives, hot-meltadhesives, solvent adhesives, and/or combinations thereof.

The first pigment and the second pigment have an acceptable wet opacity.

The first pigment and the second pigment may include TiO₂ according toan embodiment herein.

In one embodiment, the first pigment component may be present in aweight range of about 10% to about 50% of the first adhesive component,in a weight range of about 15% to about 45% of the first adhesivecomponent in another embodiment, and in weight range of from about 20%to about 40% of the first adhesive component in another embodiment. Thesecond pigment component may be present in a weight range of from about1% to about 10% of the second adhesive component.

The opacity of the label laminate 300 in wet condition may be about 80%to 100% and more particularly about 90%.

The first opacifying adhesive layer 304 may have coat weight of fromabout 13 grams per square meter (gsm) to about 25 grams per square meter(gsm) according to an embodiment herein.

The second opacifying adhesive layer 306 may have coat weight of about 6grams per square meter (gsm) to about 20 grams per square meter (gsm)according to an embodiment herein.

The pressure sensitive application may be performed on a substrate thatincludes but is not limited to glass, plastic, metal or high densitypolyethylene (HDPE) or any other substrate and commonly known materialsubstrate useful for containers.

The facestock 302 may include paper facestock, plastic facestock,multilayer laminate facestock include both paper and plastic layers, orany other face material known in the art. In certain embodiments, themultilayer laminate facestock may include a paper layer overlying aplastic layer. In some embodiments of the multilayer laminate, theplastic layer may be white or colorless, and in each condition mayexhibit varying degrees of opacity. The plastic layer may be adhered tothe paper by an adhesive. Alternatively, the plastic layer may beextruded or otherwise coated onto the paper layer. In the case of suchmultilayer laminate facestock, the opacity of the paper layer may reduceupon exposure to moisture or a liquid, while the opacity of theunderlying plastic layer may not decrease upon exposure to moisture orliquid, or the change in opacity of the underlying plastic layer uponexposure to moisture or a liquid may be different than the change inopacity of the overlying paper layer subjected to the same moisture orliquid conditions. In such cases, the opacity change in the plasticlayer may be less than the opacity change in the paper layer.

The pressure sensitive label laminate 300 exhibits loop tack which maybe greater than 14 newtons per inch (N/inch) when the facestock beingused is paper, and when the pressure sensitive application is performedon glass. In certain embodiments, the label exhibits a loop tack whichis greater than 9 N/inch when the facestock is paper and the pressuresensitive application is performed on a high density polyethylene (HDPE)substrate. However, it will be understood that the present subjectmatter includes labels exhibiting a wide array of other loop tack valuesand is not limited to any of the values described herein.

In yet another aspect of the subject matter, an opacifying adhesivecomposition adapted to remain opaque in wet condition for pressuresensitive label application is provided. The opacifying adhesive isstable under aging conditions. The opacifying adhesive includes aproportionate amount of adhesive component and a pigment componentsufficient to maintain opacity when wet while maintaining peel adhesionand loop tack in a pressure sensitive application.

The adhesive component may be selected from the group consisting ofemulsion adhesives, hot-melt adhesives, solvent adhesives, and/orcombinations thereof. The pigment component may be present in a weightrange of about 10% to about 50% of the adhesive component in someembodiments, in weight range from about 15% to about 45% of the adhesivecomponent in certain embodiments, and 20% to about 40% of the adhesivecomponent in particular embodiments. The pigment may include TiO₂. Theopacity of the label in wet condition may be in range of from about 70%to about 100% in many embodiments, from about 75% to about 95% incertain embodiments, and from about 80% to about 90% in particularembodiments. The pigment component may have higher proportion orconcentration depending upon its use in conjunction with other adhesivelayer(s) when used for maintaining opacity of the label in wetconditions.

The pressure sensitive application for the opacifying adhesive may beperformed on substrates that include but are not limited to glass,plastic, metal, high density polyethylene (HDPE) substrate or any othersubstrate known in the art useful for containers.

FIG. 4 illustrates another embodiment of a pressure sensitiveconstruction of a label laminate 400 which is adapted to remain opaquein wet environment or condition. The label laminate 400 includes anouter layer of facestock 402, an opacifying adhesive layer 404, a clearor generally transparent layer or thin metallic layer 406, a pressuresensitive adhesive layer 408, and a liner 410. Details of thesematerials and/or layers are as previously described herein.

FIG. 5 illustrates another embodiment of a pressure sensitiveconstruction of a label laminate 500 which is adapted to remain opaquein wet environment or condition. The label laminate 500 includes anouter layer of facestock 502, a layer of a pressure sensitive adhesiveor structural adhesive 504, a clear or generally transparent layer 506,an opacifying adhesive layer 508, and a liner 510. Details of thesematerials and/or layers are as previously described herein.

The present subject matter includes the incorporation of one or moreclear or transparent layers in any of the label constructions describedherein. The present subject matter also includes the incorporation ofone or more metallic layers or metal foils in any of the labelconstructions described herein. It is also contemplated that the labelconstructions can also include combinations of one or more transparentlayers and one or more metallic layers.

In a further embodiment of the subject matter, a method of preparationof an opacifying adhesive composition which is adapted to remain opaquein wet condition for pressure sensitive label application is provided.The method may include the steps of mixing a proportionate amount of anadhesive component and pigment component, and particularly with constantagitation, and continuing the mixing for about 20 minutes for anemulsion preparation for example. In many applications, mixing can beperformed for a time period of from about 5 minutes to about 30 minutes.The opacifying adhesive thus obtained does not cause any unacceptableloss of peel adhesion or tack of the adhesive component in pressuresensitive application.

The adhesive component may include acrylic emulsion adhesive. Thepigment component comprises Rutile grade aqueous TiO₂ slurry forexample.

In yet another embodiment of the present subject matter, a labeledarticle is provided. The article includes one or more labels adhered tothe article using any of the adhesives described herein and particularlythe opacifying adhesives. The construction of the label may vary but isin many applications the same or similar to the labels depicted in FIGS.1-5. FIG. 6 illustrates an example of a labeled article 600 such as abottle 602 having a label 604 adhered thereto.

EXAMPLES

The following examples are provided to illustrate the subject matter andembodiments in greater detail without however limiting the scopethereto. In the examples all parts are, ratios or percentage by weightunless otherwise noted.

Selection of the Adhesive Component of the Opacifying Adhesive Layer

The following emulsion adhesives were taken as a starting material whichincludes:

1. S2000N: Acrylic emulsion commercially available from Avery Dennison

2. S692N: Acrylic emulsion commercially available from Avery Dennison

3. AT20N: Acrylic emulsion commercially available from Avery Dennison

4. H9232: Acrylic emulsion commercially available from BASF

5. XPE1045: Acrylic emulsion internally developed by Avery Dennison

Selection of the Pigment Component of the Opacifying Adhesive Layer

The following TiO₂ slurries were taken as a starting material whichincludes:

1. Siconyl K White 00-174547: 75-76% solid slurry of TiO2 commerciallyavailable from Audia International

2. Slurry A: TiO2 slurry containing 75-76% solids

3. Slurry B: TiO2 slurry containing 75-76% solids

4. Slurry C: TiO2 slurry containing 75-76% solids

Preparation of Adhesive and TiO₂ Blend

About 10% to 50% of Rutile grade aqueous TiO₂ slurry was added into thenoted acrylic emulsion adhesives with constant agitation. The mixing wascontinued for an additional 20 minutes before being used for coating oflayers in the label laminate.

Table 1 sets forth different opacifying adhesives (OA) based uponproportions of different adhesives and pigments component. Adhesivesfree of pigment were used as controls, i.e., “CTR-1, -2, -3, and -4.”

TABLE 1 Summary of Controls and Opacifying Adhesive Compositions OA- OA-CTR-1 CTR-2 CTR-3 CTR-4 OA-1 OA-2 OA-3 OA-4 OA-5 OA-6 OA-7 OA-8 OA-9OA-10 11 12 (%) (%) (%) (%) (%) (%) (%) (%) (%) (%) (%) (%) (%) (%) (%)(%) Adhesive AT20N 100 80 S2000N 100 80 80 S692N 100 80 H9232 100 80 8085 95 XPE1045 100 85 85 85 Pigment Audia 20 20% 20 20 15 Siconyl K White00174547 Slurry B 20 20 15 5 Slurry A 15 Slurry C 15

Single Layer Opacifying Adhesive Coating as Depicted in FIG. 1

Each of the adhesives as noted above was coated onto a siliconizedpolyester/paper liner at a coat weight of 23 grams per square meter(g/m2), and then transferred onto a paper face stock (Classic WhiteUPM).

Coating of One or More Layers

Coating of one or more layer(s) of opacifying adhesive and/or adhesivelayer as illustrated in different embodiments including embodiments ofFIG. 2 and FIG. 3 can be performed by employing methods described inU.S. Pat. No. 5,962,075.

90° Peel Adhesion Test

The test samples prepared were subjected to a peel adhesion test at 90°using an Instron tensile tester on glass and high density polyethylene(HDPE) panels using a standard test protocol. Testing on the glass andHDPE panels was conducted at dwell times of 20 minutes and 24 hours.Test results are presented in Table 2 and Table 3.

Loop Tack Test

The test samples prepared as previously described were subjected to aloop tack test using an Instron tensile tester on glass and high densitypolyethylene (HDPE) panels using the standard test protocol. Testresults are depicted in Table 2 and Table 3.

Opacity: Using Hunter Lab Spectrophotometer

The wet opacity of the paper laminate was measured by using a STD testmethod known to those in the art. The opacity was measured after twohours ice bucket immersion of samples applied onto standard BYK 2810black-white opacity test cards. Results are listed in Table 2 and Table3.

Representative loop tack performances of the labels with differentopacifying adhesive formulations are shown in Table 2. In Table 2, “PT”refers paper tear.

TABLE 2 Representative Wet Opacity and Adhesive Properties of Labels ofFIG. 1 Loop Tack/ Loop Tack/ Glass HDPE Peel 90/ Wet Opacity: Adhesive +Label Laminate of FIG. 1 (N/inch) (N/inch) HDPE/Glass Paper face (%)Adhesive AT20N 11.87 9.9 PT 71.73 Only (No S2000N 20.47 13.3 PT 77.54Pigment) S692N 16.53 11.67 PT 78.76 H9232 23.03 18.8 PT 69.7 OpacifyingOpacifying Adhesives-1 7.11 8.6 PT 90.06 Adhesives OpacifyingAdhesives-2 11.87 10.01 PT 91.2 Opacifying Adhesives-3 9.09 8.88 PT91.75 Opacifying Adhesives-4 12.8 13.56 PT 88.28 Opacifying Adhesives-516.81 13.73 PT 90.66 Opacifying Adhesives-6 20.7 PT 14.44 PT 88.68Opacifying Adhesives-7 20.73 PT 12.73 PT 84.17

Representative loop tack performances of the labels with differentopacifying adhesive layer and/or adhesive layer are shown in Table 3. InTable 3, “PT” refers paper tear.

TABLE 3 Representative Wet Opacity and Adhesive Properties of Labels ofFIGS. 2 and 3 Loop Tack/ Loop Tack/ Wet Opacity: Label Laminate GlassHDPE Peel 90/ Adhesive + Construction Dual layer construction (N/inch)(N/Inch) HDPE/Glass Paper face (%) Label laminate Opacifying AdhesiveLayer: 14.8 9.48 PT 82% of FIG. 2 Opacifying Adhesives-2 Adhesive Layer:CTR-2 Label laminate First Opacifying Adhesive Layer: PT 15 PT 83% ofFIG. 3 Opacifying Adhesives-7 Second Opacifying Adhesive Layer:Opacifying Adhesives-8

Stability of the Opacifying Adhesives Under Aging Condition:

As described herein before, the opacifying adhesives maintain theirstability under aging conditions and do not adversely affect the desiredloop tack for PSA application. In Table 4 and Table 5, changes in looptack values are tabulated which are measured under various agingconditions. Coat weight used was about 23 gsm for glass substrates. ForTable 4, AVC 16699 base polymer available from Avery Dennison wasutilized as a control whereas for Table 5, the base polymer was S692Nwhich can be used as an adhesive component in the subject of the presentsubject matter. In all adhesives, pigment from Slurry A was added. InTables 4 and 5, “RT” refers to room temperature. “Tropic” refers to atemperature of 40° C. and relative humidity of 95%.

TABLE 4 Stability of Control Adhesives Remaining Adhesive level of PlusLoop tack Loop Only Pigment compared Tack-Substrate Adhesive (Slurry A)to only Glass Condition (N/inch) (N/inch) adhesive AVC 16699 RT 18.513.7 74.4% AVC 16699 60° C. 1 week 21.3 13.4 63.0% AVC 16699 Tropic 1week 17.9 13.5 75.1%

TABLE 5 Stability of Opacifying Adhesives Remaining Adhesive level ofPlus Loop tack Loop Only Pigment compared Tack-Substrate Adhesive(Slurry A) to only Glass Condition (N/inch) (N/inch) adhesive S692N RT13.4 10.1 75.0% S692N 60° C. 1 week 14.2 10.7 75.6% S692N Tropic 1 week13.5 10.8 80.2%

A comparison of loop tack values reported in Table 4 and Table 5suggests that the present subject matter opacifying adhesives havealmost nil impact on aging and thus are stable.

Additional evaluations were performed to assess peel adhesion andloop-tack of opacifying adhesives after wetting.

TABLE 6 Formulations and Opacity after Two Hours in Ice Bucket OA-9OA-10 OA-11 OA-12 Adhesive XPE1045 100 85 85 85 Pigment Slurry A 15Siconyl K White 15 00-174547 Slurry C 15 Opacity (%) 58.78 84.03 83.2083.80

XPE1045 is an acrylic emulsion adhesive internally developed by AveryDennison. Face material used for the opacity measurement was ClassicWhite paper UPM China.

Table 7 shows the impact of white pigment on the loop tack.

To exclude the impact of the face paper, a clear polypropylene film(PP60 available from Avery Dennison) was used. During aging testsmaterials from a paper face might migrate into the adhesive, which couldhave a negative impact. To exclude the possible effect of the facepaper, a filmic polypropylene face was utilized. “RT” and “Tropic” havethe same meanings as previously noted.

TABLE 7 Effect of White Pigment on Loop Tack OA-9 OA-10 Adhesive XPE1045100 85 Pigment Slurry A 15 Loop Tack Glass RT aged (N/inch) 13.2 10.8 %left of clear adhesive 81.8% Loop Tack Glass 60° C. aged (N/inch) 12.710.43 % left of clear adhesive 82.1% Loop Tack Glass tropic aged(N/inch) 13.67 9.95 % left of clear adhesive 72.8% Loop Tack HDPE RTaged (N/inch) 5.35 4.5 % left of clear adhesive 84.1% Loop Tack HDPE 60°C. aged (N/inch) 6.13 6.64 % left of clear adhesive 108.3% Loop TackHDPE tropic aged (N/inch) 6.86 5.17 % left of clear adhesive 75.4%

The use of different grades of TiO₂ was also investigated. The testedTiO₂ types differed in type, stabilization compound, percentage TiO₂ andoil absorption.

TABLE 8 Chemical and Physical Characteristics of the Different Grades ofTiO₂ Stabilized with Oil compounds TiO₂ absorption Supplier & of thesecontent Density (ISO 787/ Grade Type elements (wt % min.) (g/cm3) 5)Kronos 2044 Rutile Al, Si 82 3.6 41 Kronos 1002 Anatase — 99 3.7 19Dupont Rutile Al, Si 93 4 13.9 R-706

In this evaluation, the slurry was prepared by blending the noted TiO₂powder with water under stirring. No additives such as dispersants wereadded. The prepared slurry was added to the adhesive under mixing.

Table 9 shows the formulations and loop tack results. Face material waspolypropylene. No paper was used to exclude potential interaction withagents/components migrating out of the paper into the adhesive. Theadhesive and pigments used are those described in conjunction withTables 7 and 8. In Table 9, “RT” and “Tropic” have the same meanings aspreviously noted.

TABLE 9 Loop Tack Results OA-13 OA-14 OA-15 Adhesive XPE1045 85 85 85Pigment K1002 15 K2044 15 R706 15 Loop Tack Glass RT aged 8.1 8.3 8.3(N/inch) Loop Tack Glass 60° C. 9.1 9.4 9.7 aged (N/inch) Loop TackGlass tropic aged 9.5 9.7 10.6 (N/inch) Loop Tack HDPE RT aged 6.2 6.17.3 (N/inch) Loop Tack HDPE 60° C. 6.3 6.0 7.2 aged (N/inch) Loop TackHDPE tropic aged 6.1 5.9 7.7 (N/inch) Opacity, see Table 10 — — —

Table 9 shows there is substantially no difference in loop tack betweenthe tested TiO₂ grades. These results demonstrate new and unexpectedproperties because it would be expected that uncoated TiO₂ and TiO₂ witha high oil absorption would have a negative impact on adhesivestability. Also the wet adhesive was stable and easy to coat using slotdie techniques.

In still additional evaluations, the effect of coating paper withopacifying adhesive upon dry opacity and wet opacity was investigated.The paper used was Centaure Blanc from Arjo Wiggins. As shown below inTable 10, when the paper is dry the opacity improvement because of thewhite adhesive is only 3 to 4.4 (delta opacity dry). When the paper iswet then this difference is 13 to 20. This clearly shows the benefit ofthe white adhesive under wet conditions (delta opacity wet).

TABLE 10 Effects on Dry and Wet Opacity Dry Opacity Wet Opacity OA-13OA-14 OA-15 OA-13 OA-14 OA-15 Adhesive XPE1045 85 85 85 85 85 85 PigmentK1002 15 15 K2044 15 15 R706 15 15 Opacity of paper with opaque 93.894.5 95.2 78.3 79.4 85.5 adhesive (%) Opacity of dry paper (no adhesive)(%) 90.8 90.8 90.8 Opacity of wet paper (no adhesive) (%) 65.3 65.3 65.3Delta opacity dry = dry paper + opaque adhesive 3.0 3.7 4.4 opacity −dry paper opacity Delta opacity wet = wet paper + opaque adhesive 13.014.1 20.2 opacity − wet paper opacity

In yet another series of evaluations, peel adhesion was investigated.Table 11 summarizes peel adhesion values measured for samples using anopacifying adhesive including S692N and Slurry A as pigment. The sampleswere prepared using clear polypropylene film PP60.

TABLE 11 Peel Adhesion Peel Adhesion Bond Time = 24 h OA-16 OA-17Adhesive 5692N 100 85 Pigment Pigment Slurry - A 15 Peel Adhesion 90Glass RT aged 13.5 10.8 % left of clear adhesive 80.0% Peel Adhesion 90Glass 60 C. aged 6.8 6.1 % left of clear adhesive 90.0% Peel Adhesion 90Glass tropic aged 6.0 5.0 % left of clear adhesive 83.3% Peel Adhesion90 HDPE RT aged 6.0 4.5 % left of clear adhesive 75.0% Peel Adhesion 90HDPE 60 C. aged 4.7 4.5 % left of clear adhesive 94.7% Peel Adhesion 90HDPE tropic aged 4.0 3.1 % left of clear adhesive 77.5%

Table 12 summarizes peel adhesion values measured for samples using anopacifying adhesive including XPE1045 and Slurry A as pigment. Thesamples were prepared using clear polypropylene film PP60.

TABLE 12 Peel Adhesion Peel Adhesion Bond Time = 24 h OA-9 OA-10Adhesive XPE1045 100 85 Pigment Slurry A 15 Peel Adhesion 90 Glass RTaged 17.9 13.5 % left of clear adhesive 75.4% Peel Adhesion 90 Glass 60C. aged 11.3 6.9 % left of clear adhesive 61.1% Peel Adhesion 90 Glasstropic aged 10.6 6.2 % left of clear adhesive 58.5% Peel Adhesion 90HDPE RT aged 9.8 7.1 % left of clear adhesive 72.4% Peel Adhesion 90HDPE 60 C. aged 6.6 5.8 % left of clear adhesive 87.9% Peel Adhesion 90HDPE tropic aged 5.3 3.99 % left of clear adhesive 75.3%

It will be understood that an opacity range of 80% to 90% may alsoencompass opacity of more than 80% or 90% for visible light or similarwavelength(s).

Thus, specific compositions and embodiments of the opaque adhesivecomposition or the label laminate have been disclosed. It should beapparent, however, to those skilled in the art that many moremodifications besides those already described are possible withoutdeparting from the aspects described herein. The present subject matter,therefore, is not to be restricted except in the spirit of thedisclosure. Moreover, in interpreting the disclosure, all terms shouldbe interpreted in the broadest possible manner consistent with thecontext. In particular, the terms “comprises” and “comprising” should beinterpreted as referring to elements, components, or steps in anon-exclusive manner, indicating that the referenced elements,components, or steps may be present, or utilized, or combined with otherelements, components, or steps that are not expressly referenced.

Many other benefits will no doubt become apparent from futureapplication and development of this technology.

All patents, applications, standards, and articles noted herein arehereby incorporated by reference in their entirety.

The present subject matter includes all operable combinations offeatures and aspects described herein. Thus, for example if one featureis described in association with an embodiment and another feature isdescribed in association with another embodiment, it will be understoodthat the present subject matter includes embodiments having acombination of these features.

As described hereinabove, the present subject matter solves manyproblems associated with previous strategies, systems and/or devices.However, it will be appreciated that various changes in the details,materials and arrangements of components, which have been hereindescribed and illustrated in order to explain the nature of the presentsubject matter, may be made by those skilled in the art withoutdeparting from the principle and scope of the claimed subject matter, asexpressed in the appended claims.

What is claimed is:
 1. A label adapted to remain opaque in wetcondition, said label comprising: an outer layer of facestock forreceiving printed indicia; at least one opacifying adhesive layerunderlying said facestock, wherein said opacifying adhesive layercomprises an adhesive component and a pigment component in proportionsufficient to maintain opacity when exposed to an aqueous environmentand a peel adhesion of at least 1 N/inch and a loop tack of at least 2N/inch of the opacifying adhesive layer in a pressure sensitiveapplication; and a liner, underlying said opacifying adhesive layer. 2.The label of claim 1, wherein said adhesive component is a pressuresensitive adhesive.
 3. The label of claim 1, wherein said adhesivecomponent is selected from the group consisting of emulsion adhesives,hot-melt adhesives, solvent adhesives, and combinations thereof.
 4. Thelabel of claim 1, wherein said pigment component has acceptable wetopacity.
 5. The label of claim 1, wherein said pigment component ispresent in a weight range of about 10% to about 50% of said adhesivecomponent.
 6. The label of claim 1, wherein said pigment componentincludes TiO₂.
 7. The label of claim 1, wherein said label furthercomprises an adhesive layer underlying said facestock.
 8. The label ofclaim 7, wherein said adhesive layer is selected from the groupconsisting of emulsion adhesives, hot-melt adhesives, solvent adhesives,and combinations thereof.
 9. The label of claim 1, wherein said adhesivecomponent includes acrylic adhesive.
 10. The label of claim 1, whereinsaid opacity in wet condition is about 80% to 90%.
 11. The label ofclaim 1, wherein said pressure sensitive application is performed on asubstrate comprising glass.
 12. The label of claim 1, wherein saidpressure sensitive application is performed on a high densitypolyethylene (HDPE) substrate.
 13. The label of claim 1, wherein saidfacestock comprises a paper facestock.
 14. The label of claim 1, whereinsaid facestock comprises a plastic facestock.
 15. The label of claim 1,wherein said loop tack is at least 3 newtons per inch (N/inch) when saidfacestock is paper, and when said pressure sensitive application isperformed on a glass substrate.
 16. The label of claim 1, wherein saidloop tack is at least 2 newtons per inch (N/inch) when said facestock ispaper, and when said pressure sensitive application is performed on ahigh density polyethylene (HDPE) substrate.
 17. The label of claim 1,wherein said opacifying adhesive layer has a coat weight of about 16 toabout 30 grams per square meter (gsm).
 18. The label of claim 1, whereinsaid opacifying adhesive layer has a coat weight, of about 22 to about26 grams per square meter (gsm).
 19. The label of claim 7, wherein theloop tack of the label is at least 3 newtons per inch (N/inch) when saidfacestock is paper, and when said pressure sensitive application isperformed on a glass substrate.
 20. The label of claim 7, wherein theloop tack of the label is at least 2 newtons per inch (N/inch) when saidfacestock is paper, and when said pressure sensitive application isperformed on a high density polyethylene (HDPE) substrate.
 21. The labelof claim 1 further comprising: a clear or transparent layer.
 22. Thelabel of claim 1 further comprising: a metallic layer.
 23. A labeladapted to remain opaque in wet condition for pressure sensitiveapplication, said label comprising: an outer layer of facestock forreceiving printed indicia; a first opacifying adhesive layer and asecond opacifying adhesive layer, wherein said first opacifying adhesivelayer underlies said facestock, wherein said second opacifying adhesivelayer underlies said first opacifying adhesive layer, wherein said firstopacifying adhesive layer includes a first adhesive component and afirst pigment component in a proportion sufficient to maintain opacitywhen exposed to an aqueous environment and a peel adhesion of at least 1N/inch and a loop tack of at least 2 N/inch of said first opacifyingadhesive layer in said pressure sensitive application, wherein saidsecond opacifying adhesive layer includes a second adhesive componentand a second pigment component in a proportion sufficient to maintainopacity when exposed to an aqueous environment and a peel adhesion of atleast 1 N/inch and a loop tack of at least 2 N/inch of said secondopacifying adhesive layer in said pressure sensitive application; and aliner underlying said second opacifying adhesive layer.
 24. The label ofclaim 23, wherein said first adhesive component and said second adhesivecomponent are each independently selected from the group consisting ofemulsion adhesives, hot-melt adhesives, solvent adhesives, andcombinations thereof.
 25. The label of claim 23, wherein said firstpigment and said second pigment each has an acceptable wet opacity. 26.The label of claim 23, wherein said first pigment and said secondpigment comprises TiO₂.
 27. The label of claim 23, wherein said firstpigment component is present in a weight range of about 10% to about 50%of said first adhesive component.
 28. The label of claim 23, whereinsaid second pigment component in present in a weight range of about 1%to about 10% of said second adhesive component.
 29. The label of claim23, wherein said opacity in wet condition is about 80% to 90%.
 30. Thelabel of claim 23, wherein said first opacifying adhesive layer has coatweight of about 13 grams per square meter (gsm) to about 25 grams persquare meter (gsm).
 31. The label of claim 23, wherein said secondopacifying adhesive layer has coat weight of about 6 grams per squaremeter (gsm) to about 20 grams per square meter (gsm).
 32. The label ofclaim 23, wherein said pressure sensitive application is performed on asubstrate that comprises glass.
 33. The label of claim 23, wherein saidpressure sensitive application is performed on a substrate thatcomprises high density polyethylene (HDPE).
 34. The label of claim 23,wherein said facestock is a paper facestock.
 35. The label of claim 23,wherein said facestock is plastic facestock.
 36. The label of claim 23,wherein said loop tack is at least 3 newtons per inch (N/inch) when saidfacestock is paper and when said pressure sensitive application isperformed on a high density polyethylene (HDPE) substrate.
 37. The labelof claim 23 further comprising: a clear or transparent layer.
 38. Thelabel of claim 23 further comprising: a metallic layer.
 39. Anopacifying adhesive composition adapted to remain opaque in wetcondition for pressure sensitive label application, said opacifyingadhesive comprising a proportionate amount of adhesive component and apigment component sufficient to maintain opacity when exposed to anaqueous environment for at least 1 hour and a peel adhesion of at least1 N/inch and a loop tack of at least 2 N/inch in said pressure sensitiveapplication.
 40. The opacifying adhesive composition of claim 39,wherein said adhesive component is selected from the group consisting ofemulsion adhesives, hot-melt adhesives, solvent adhesives, andcombinations thereof.
 41. The opacifying adhesive composition of claim39, wherein said pigment component is present in a weight range of about10% to about 50% of said adhesive component.
 42. The opacifying adhesivecomposition of claim 39, wherein said pigment component comprises TiO₂.43. The opacifying adhesive composition of claim 39, wherein saidopacity in wet condition is about 80% to 90%.
 44. The opacifyingadhesive composition of claim 39, wherein said pressure sensitiveapplication is performed on a substrate selected from the groupconsisting of glass and high density polyethylene (HDPE) substrate. 45.A method of preparation of an opacifying adhesive composition which isadapted to remain opaque in wet condition for pressure sensitive labelapplication, said method comprising the steps of: mixing a proportionateamount of an adhesive component and pigment component with agitation;and wherein said opacifying adhesive does not cause any unacceptableloss of peel adhesion or tack of the adhesive component in pressuresensitive application.